According to witnesses, the weapons were fired near the consulate in Clifton Block 4 around 9.30am local time (4.30am GMT). At least two policemen were shot dead in the attack and a security guard was wounded. Local media reported that the injured had reached Jinnah hospital.
It is not yet clear whether Chinese officials were harmed but Karachi police chief Amir Shaikh confirmed the attackers were not able to get inside the consulate.
Mr Sheikh said: “They tried to enter the visa section but did not succeed.”
Pakistan’s insurgent separatist militant group Balochistan has claimed responsibility for the attack and asserted that their action “is continuing”.
The spokesman for the Balochistan Liberation Army, Geand Baloch, told Reuters: “There were three suicide attackers.
“They stormed the Chinese embassy in Karachi.
“China is exploiting our resources.”
Footage on social media showed smoke arising from around the area.
An eyewitness told Express.co.uk that the area “has now been cleared”.
He added: “All three terrorists are killed.
“I saw some smoke in the parking and lawn area of the embassy, not sure whether they got inside the building or not.”
Police officials said that one suicide vest had been recovered, and bomb squad members were on the scene to dispose of the other explosives.