Transport officials say they are hopeful Sydney's train system will now be operating as usual after thunderstorms knocked out vital infrastructure on New Year's Eve.

On Tuesday night - more than 20 hours after lightning and storms struck on New Year's Eve, damaging overhead wiring and signal equipment - Sydney Trains were still struggling with massive delays.

Tens of thousands of people who had converged on the harbour city for festivities crowded into stations and spilled onto streets waiting for trains arriving late and sometimes not at all.

Despite the NSW government encouraging people to leave cars at home and catch public transport in the lead up to the celebrations, many thousands were unable to leave the city for hours.

Authorities blamed the "freak" thunderstorms and record crowds putting massive pressure on the transport network.

AAP

However, Premier Gladys Berejiklian confirmed there is no plan to provide commuters with a refund or compensation.

"That is not currently in our plans, no," she told reporters in Sydney on Tuesday.

Biwa Kwan

NSW Opposition leader Michael Daley said the government's handling of the situation is "just not good enough".

"What an international embarrassment this is," he said comparing the organisation for the fireworks with the meltdown on Sydney trains.

"The [train] system has got to get over a bit of rain. Eighteen hours later there is still a shutdown. There's something seriously wrong here, and the premier has to explain why."

He accused the government of cutting maintenance to the point the system was failing under slight strain.

AAP

Wild weather battered Sydney on Monday evening, causing extensive delays and cancellations across the network.

Multiple major city-bound lines were affected from 6pm on Monday, including T1, T2, T3 and T8.

0:00 Sydney Trains CEO apologises for NYE delays 00:00 / 00:00 Share Share on Twitter

Share on Facebook

A spokesman for Sydney Trains apologised to commuters for the delays, saying staff had been working around the clock to resolve the issues.

Read more Australia welcomes 2019 in spectacular style

"A substantial amount of work went into rectifying those faults, with engineers working through those storms to rectify those problems," he said.

"I would certainly like to apologise to customers who were frustrated last night."

Frustrated commuters criticise delays

On New Year's Eve Transport for NSW issued warnings that numerous lines had been affected by lightning striking infrastructure including signal boxes, while police and security staff tried to corral swelling crowds.

This is why I drive everywhere. Sydney Trains now sending the train on empty and telling people to “consider alternative arrangements” to get to their destination. On New Year’s Eve. Due to signal failure. pic.twitter.com/HO6ZnPlkf9 — Rick (@RickIsAce) December 31, 2018

Angry commuters vented online, with some reporting delays of two-and-a-half hours on a city-bound train from Lidcombe on Monday night.

Guard announcement: "I wouldn't rely on this train if I were you. I'd recommend a cab".



Outstanding stuff!#SydneyTrains #SydNYE — Oscar (@mightydragons) December 31, 2018

Guard announcement - estimates 1hr 15min to go from Chatswood to the city. Pathetic. Not to mention the government is still charging full peak hour fares. #SydneyTrains #SydNYE #notgoodenough — Oscar (@mightydragons) December 31, 2018

#sydneytrains Massive breach of trust in this system. At this point, who would be stupid enough to use public transit in an emergency / natural disaster? No announcements!? #Pathetic. Driverless trains would have done a better job at keeping passengers informed. @smh @abcnews — Art Vandelay (@avandelay20) January 1, 2019

- with AAP.