The father of a Palestinian toddler killed in a West Bank arson attack blamed on Jewish extremists has died of his injuries, a relative has said.

Last week's firebomb attack on the family's house in Ramallah killed 18-month-old Ali Dawabsheh. Ali's parents and a four-year-old brother were also injured in the attack.

Nasser Dawabsheh, the toddler's uncle, said the family was informed early today that Ali's father, Saed, had died at Israel's Sorroka Hospital.

He will be buried later today.

The attack prompted pledges by Israel's government to get tougher on Jewish vigilantes who have repeatedly attacked Palestinians over the years.

Critics say Israeli authorities do little to enforce the law against militant settlers and that the military has failed to protect Palestinians against such attacks.