The World Health Organisation (WHO) has updated its advice for the public in relation to Zika virus transmission.

It says this is based on "new evidence and advice".

The primary transmission route of the virus, which can cause birth defects in newborn babies, is from the Aedes mosquito.

However, the WHO now says there is "mounting evidence" that sexual transmission is possible - and more common than previously assumed.

"This is of concern due to an association between the Zika virus and adverse pregnancy outcomes,  including microcephaly, neurological complications and Guillain-Barré syndrome", it says.

In its latest advice, it quotes 17 studies or reports that have been published on sexual transmission of Zika, including:

• Seven studies on symptomatic male to female transmission
  One study on male to male transmission
  One study on female to male transmission
  Eight studies published on the presence of Zika virus in semen

It is advising people in regions where Zika is present to ensure that all men and women with infection and their sexual partners receive information about the risks of sexual transmission of the virus.

It is also recommending that both men and women get counselling on safer sexual practices, and be offered condoms.

"The consistent use of condoms is essential to prevent sexually transmitted infections, including human immunodeficiency virus (HIV), and unwanted pregnancy", the WHO adds.

While in regions where Zika is not present, the health body is recommending that men and women returning from areas where transmission of the virus is known should adopt "safer sex practices or consider abstinence" for at least six months upon return.

It also says couples or women planning a pregnancy, who are returning from areas where transmission of Zika is known are advised to wait at least six months before trying to conceive.

Some 72 countries and territories have reported evidence of Zika virus transmission since 2007, with 69 with reports from 2015.

Fifty-five of those first reported an outbreak from 2015 onward.

While since February 2016, 11 countries have reported evidence of person-to-person transmission.