DHAKA (AFP) - Bangladesh's opposition leader Khaleda Zia Saturday left Prime Minister Sheikh Hasina waiting on her doorstep after she had come to offer her condolences following the sudden death of Zia's youngest son.

Live footage aired by local television stations showed Hasina's motorcades, escorted by high security, standing in front of Zia's office in Dhaka's upmarket Gulshan district.

Zia's son Arafat Rahman Koko, 44, died of a heart attack in Malaysia on Saturday, devastating the two-time former prime minister, who launched a new rounds of protests earlier this month to topple bitter rival Hasina.

In an apparent snub, Zia's aide said she was asleep at her office when Hasina came to visit.

Zia and Hasina are known as the "Battling Begums" for their bitter rivalry that poisoned Bangladeshi politics for nearly three decades.

"Begum" is an honorific title given to respected Muslim women.

"She became unwell after hearing the tragic death of her son. We gave her medicine and she went to sleep," Zia's private secretary Shimul Biswas said.

"We've requested the Prime Minister to come at another time as she was asleep," he added.

Hasina's aides reacted sharply.

"She came as a prime mister, as a leader and as a mother to console a mother. She stood there for five minutes but she was not allowed to enter," Iqbal Sobhan Chowdhury, a spokesman for Hasina, told reporters.

"It's against any political norms and it's inhumane," he added.

Opposition officials have said that the death of Zia's son will not change her resolve to maintain a nationwide transport blockade called early this month in a bid to force an early election.

The protests have unleashed deadly violence, leaving at least 30 people dead and injuring hundreds more.