(AFP) - Prime Minister Mahathir Mohamad is a workaholic and a compulsive reader who doesn't spend enough time with his family, his wife said in an interview published today.

First lady Siti Hasmah Mohamed Ali told the New Sunday Times that she sometimes got frustrated because her husband, who has ruled Malaysia for two decades, worked too hard.

"The first and third Saturdays (of the month) are holidays for civil servants. This is for them to be with their family but unfortunately not so for us," she said.

"I grumble about this to the PM: you give people off on Saturdays to be with their families but you are not with us."

No clue when husband will quit

Siti Hasmah, who has been married to the premier for 45 years, described Mahathir as a "very good husband and a very good father."

"The grandchildren love him. He needs to have more time to be with us. As a husband, he's very considerate... he is a very kind person, very caring," she said.

Mahathir is also an avid reader who is "very knowledgeable," she said.

"He is a compulsive reader. Leave him alone in a bookstore and he will come out with so many books. He is very inquisitive, he wants to know everything," she said.

Siti Hasmah said she has no clue when Mahathir, who came into power in 1981 and is the country's longest-serving prime minister, would retire.

"I really don't know but when he retires, he says he wants to write. He has been writing but hasn't got much time to write what he wants. We often take vacations, get on a boat and cruise where nobody can disturb us.

"That's what he wants to do if he retires."

Mahathir and Siti Hasmah, both 75 and both doctors by profession, have three daughters and four sons.