One year after Israel's offensive on the Gaza Strip, the spokesman for Hamas' armed wing said this week that the Islamist group would not shirk away from a new battle with Israel.

"We do not wish for war. We wish for calm and peace for our people," Abu Ubaida, Izz el-Deen al-Qassam Brigades spokesman told Reuters.

"But if any battle is imposed on us, we are ready with all our manpower and equipment to confront any Zionist war, any crime and any attack regardless of scale," he added.

Israel has said the brigades, which some observers estimate have 25,000 fighters, have been seeking with Syrian and Iranian help to upgrade their rocket capabilities and put the Israeli heartland and the commercial capital of Tel Aviv within range.

Abu Ubaida said Hamas had no choice but to improve its arsenal.

"The enemy is developing its weapons and is using internationally banned weapons against us," he said, without giving details.

"Therefore, we have the right to use any weapon that we deem suitable and we have the right to get into [Gaza] any weapon that we see as appropriate in the ongoing battle with the occupation," Abu Ubaida said, using Hamas' term for Israel.

He declined to elaborate on Hamas' weaponry. Observers close to the group said Hamas, which rules Gaza, was also developing more effective anti-tank weapons and training to improve battlefield tactics.

"The nature of our battle with the enemy requires that we do not announce the nature of our capabilities and the weapons we possess until we use them to confront any upcoming aggression against the Gaza Strip," he said.

Abu Ubaida urged Egypt to stop building a steel wall along its border with the Gaza Strip.

He declined to comment on weapons-smuggling via a network of tunnels through which commercial goods are also brought into the territory, which is under an Israeli-led blockade.

Israel tightened its Gaza border restrictions after Hamas seized the enclave from Fatah forces loyal to Palestinian President Mahmoud Abbas in 2007. Hamas has spurned Western demands to recognize Israel, renounce violence and accept existing interim Israeli-Palestinian peace deals.

Calm has largely returned to the Israel-Gaza frontier since Israel's three-week offensive last year, an operation it said it launched to end cross-border rocket attacks by Palestinian militants.

Abu Ubaida said the Gaza war, in which 1,300 Palestinians and 13 Israelis were killed, had stirred thousands of Gaza residents to volunteer to join the ranks of the Qassam brigades.

Israel and Hamas are currently negotiating, through a German mediator, a deal under which Israel would release hundreds of Palestinian prisoners in return for an Israeli soldier captured in 2006 by Gaza militants who tunnelled across the border.