Visits will resume in specific care homes in England once local directors of public health and local authorities decide it is safe to do so, the Department of Health and Social Care (DHSC) said.
Now the rate of community transmission of coronavirus has fallen, the Government has issued the guidance to help care homes resume visits while keeping residents and staff protected.
But Professor Martin Green, chief executive of the membership body Care England, said this should have been published last month.
Providers previously expressed "immense frustration" over the delay, which prompted some care associations to develop their own protocols for care homes wishing to resume visits earlier.
The new guidance says visits should be limited to a "single constant visitor" per resident where possible to limit the risk of infection spread and keep footfall in and out of the home down.
It is understood care homes will have discretion to work with families so individuals can visit their loved ones separately, for example if an elderly person has more than one child.
But care homes, with the local directors of public health, will have the final say on this based on the local circumstances.
Risk assessments will be undertaken prior to visits starting, and visits should involve face coverings and social distancing measures.
More personal protective equipment will be required if a visitor is making close personal contact with a resident, but this should be kept to a minimum.
If there is an outbreak in the home or evidence of increased transmission in the community which leads to a local lockdown, care homes should rapidly impose visiting restrictions.
It is understood that in the absence of Government guidance until now, some care homes in England have, since June, allowed socially distanced visits in outdoor areas if the facility has been free from Covid-19 for a certain period.
Care England produced its own document for members on visiting learning disability providers on June 10 and supported a visitors protocol for residential care providers produced by the Care Provider Alliance on June 19.
The membership organisation, the country's largest representative body for independent providers of adult social care, said it was "disappointed" the Government guidance had come so late.
Prof Green said: "This guidance should have been with care providers last month.
"We are at a loss to understand why the Department of Health and Social Care cannot act quickly in a crisis or why it is deaf to the comments and input from the sector."
He added the guidance does not consider issues around visitors and residents leaving the premises, with many relatives likely to want to take their loved ones out.
Health and Social Care Secretary Matt Hancock said: "I know how painful it has been for those in care homes not being able to receive visits from their loved ones throughout this period.
"We are now able to carefully and safely allow visits to care homes, which will be based on local knowledge and circumstances for each care home.
"It is really important that we don't undo all of the hard work of care homes over the last few months while ensuring families and friends can be safely reunited, so we have put in place guidance that protects everyone."
The guidance says providers should encourage visitors to wear a face covering and wash their hands thoroughly before and after it is used.
They should wear appropriate further personal protective equipment depending on the need of their visit, including gloves and aprons.
Providers should also consider whether visits could take place in a communal garden or outdoor area, accessible without going through a shared building.
Guidance for supported living settings will be published shortly, the DHSC said.