Hi,
It is dependent on the current the LED has to consume to light up the LED.
The GPIO pin of LPC5516 can provide 4mA current, if 4mA current can light up the LED, it is okay, you can connect a serial resistor (3.3V-0.7V)/4mA=650 ohm to limit the current.
If the 4mA is not enough to light up the LED, pls connect a transistor.

copied from data sheet of LPC551x.
AS the above table, both the source/sink current of each GPIO is 4mA.
Hope it can help you
BR
XiangJun Rong