Former Wales Women wing Caryl James fears the Welsh Rugby Union (WRU)'s plan to name one coach for both the national 15-a-side and Sevens teams would be "too much" for one person.
WRU chief executive Martyn Phillips and performance director Ryan Jones are seeking someone for the role.
"I had a massive shock to see the job description. It's a job for three or four people," said James.
"I don't know who in the world can perform all these duties."
Rowland Phillips left his role as head coach of Wales Women 15-a-side officially in March 2020.
His successor will take charge of Wales Women Sevens as well as the 15-a-side team, with the ambition of guiding Wales to close the gap on the world's leading nations.
"I was glad to hear the Union finally saying clearly that there were plans in place to advertise for a head coach. Better late than never I'd say," James told BBC Radio Cymru.
She said it would be "virtually impossible" for anyone to make a success of the role, adding: "It's too much responsibility for one person, and you'll be halving the pool of coaches you can select from by asking for someone who can do both roles.
"Both games are totally different. We have 15-a-side experts and seven-a-side experts, so I think that will halve the number of coaches that will apply.
"Who can do both roles to the standard they have advertised for?"
The WRU expect further coaches will be appointed in due course to complement the skill set of the successful head coach of the women's programme.
James says former Wales players Rachel Taylor and Liza Burgess could be candidates for the full version of the game, but neither has significant sevens coaching experience.
"For the 15-a-side team you've got someone like Rachael Taylor," said James.
"She's a former player and captain, she's coaching at a high level nationally already, but not much seven-a-side experience.
"Then there's Liza Burgess who also has vast experience of the 15-a-side game but not seven-a-side. So it's a huge task to find someone who can do both roles."
James also welcomed WRU plans to contract players professionally in future.
"I was expecting this to happen some years ago," said James.
"It's good to hear this now, but Wales are under such a disadvantage because other countries have moved on to professional contracts.
"There are 28 fully professional contracts in England already. France and other nations are so far ahead of us. But this is good news.
"It's the first time we've heard the [WRU] chief executive say that contracts are on the horizon to our players who are sacrificing so much to wear the red jersey.
"So I'm sure this will be an incentive and a boost for them, that all this hard work they put in as amateurs will be worth it."