Two Hamas fighters were killed on Wednesday after a tunnel linking the besieged Gaza Strip to Egypt's Sinai Peninsula collapsed, the Islamist rulers' military wing has said.

"The two men in their twenties were killed after an accident caused the tunnel to collapse," al-Qassam Brigrades said in a statement.

The statement identified the two men as Ismail Abdul Karim Shamali and Rami Mounir al-Are'er.

Rescue teams are still searching for other missing men who may have been inside the tunnel when it collapsed.

The incident comes only days after four Palestinian workers were killed in another tunnel collapse due to flooding believed to be carried out by the Egyptian military.

Hamas has repeatedly accused Egypt of strengthening Israel's siege of Gaza by destroying the tunnels which have long been used to transport people and much-needed goods in and out of the enclave of two million inhabitants.

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The Egyptian army did not confirm the information, though it has destroyed hundreds of tunnels in the area, alleging they are used to transport arms and militants.

Despite Egypt's systematic attempts to destroy the tunnels in Gaza, many Palestinians have continued to carry out increasingly perilous work underground.

In recent months, at least 20 Gazans have been killed in both militant and smuggling tunnels in the strip.

An Israeli blockade severely restricts the movement of people and goods into and out of the territory, and Egypt's sole border with Gaza has remained largely closed since the toppling of Islamist President Mohamed Morsi in 2013.